Cruising quietly through the English countryside, it’s comforting to know that this car’s only emissions could be watering the wayside weeds.

Oxygen from the front air vent reacts with hydrogen pumped from carbon-fibre tanks at the rear to generate electricity in the heart of this hydrogen fuel cell car.

The only by-product is water – which the car discharges from its tailpipe as it glides between green fields and bluebells.

“Hydrogen is the most abundant element in the universe and anything that uses energy can be powered by it,” says Jon Hunt, Toyota UK’s alternative fuels marketing manager. “We think hydrogen offers the greatest future potential for decarbonising transport.” 

Hunt is my companion as I test drive the Toyota Mirai – which means “future” in Japanese – along the roads of southern England. The car can cover around 480 kilometres (300 miles) on a full tank of 5 kg of hydrogen, which currently costs around £50 ($65) in the UK. That amount of fuel can be produced from 50 litres of water.

Hydrogen can also be captured from industrial processes and even from the fermentation of biomass.

If it is produced at pump stations using renewable power to split water into hydrogen and oxygen, the fuel creates practically no emissions. Because it can be stored indefinitely, it can also help make the most of any surplus renewable power, helping to manage fluctuations in wind and solar supplies.

Promising future  

Hydrogen is in its infancy as a transport fuel. But with some of the world’s leading engineering and energy companies exploring its potential, hydrogen could play a critical role in lowering global carbon emissions, while improving local air quality.

An increasing number of hydrogen buses operate in cities around the world and a fuel-cell train is currently being tested in Germany.

The car components are no more expensive than modern diesel engines, but current low production levels mean the overall cost of making each fuel-cell car is relatively high.

Toyota made around 1,600 Mirais in 2015, around 2,000 in 2016 and expects to make around 3,000 in 2017.

As production rises the price of each car should fall, Hunt says. The long-term cost of owning a fuel-cell car is also relatively low because, unlike batteries, fuel cells don’t wear out.

Inside Energy (Toyota Hydrogen Shoot).

Hitting the highway 

The Mirai accelerates strongly and smoothly as we drive onto the M25 motorway around London. It can do 0-100 kilometres per hour (or 0-60 miles per hour) in less than 10 seconds and, with a top speed of around 180 kilometres per hour, has plenty of power for highway driving.

A few miles down the road we pull into Cobham services, home to Shell’s first hydrogen filling station in the UK. It uses electricity from renewable sources to make hydrogen from water. Like petrol-electric hybrids, the Mirai recovers energy from its brakes to top up the battery as we slow to a standstill at the hydrogen pump and storage tank. 

“The car scavenges and redistributes power in whichever way is most efficient,” Hunt says.

I flip open the fuel flap on the rear passenger side. The entry pipe is slimmer than on a standard car.

To avoid any leaks, the pump nozzle connects firmly onto the car’s input pipe before sensor systems on both sides check that the connection is air-tight. Then, once I’ve paid at the pump using a special charge card that comes with the car, it automatically dispenses the fuel.

After a few minutes we are off again, fully fuelled and heading back down the motorway towards Toyota’s futuristic UK headquarters.

The test drive is over, but the Mirai still has a surprise in store. There is a button under the dashboard that purges water from the car.

Hunt tells me we could have made a hot drink with the water from the tailpipe, it’s that pure. But he forgot to bring his portable water boiler. And tepid tailpipe water doesn’t sound like my cup of tea.

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